Fabric care appliances designed to clean articles of clothing include washers and dryers. A typical dryer includes a drum, which receives pre-washed articles of clothing therein. Activation of the dryer causes the drum to rotate while heated air is passed into and out of the drum. The clothes, and more particularly the water content therein, is heated sufficiently to change the water from a liquid to a gas (vaporization), whereupon the water vapor is ejected with the exiting airflow, and the clothes are “dried.”
Gas dryers, which use electricity to power various electrically operated components (such as a motor, timer, buzzer alarms, lights, and other “on-board” electrical devices), are labeled as gas dryers because they use gas valves and other gas-related components to allow for heat to be generated for use in the drying process. In contrast, electric dryers do not incorporate any gas components but instead have air-to-air electrical heat resistance element coils allowing for the generation of heat for the drying process.
Despite their popularity, conventional clothes dryers have a number of drawbacks. First among these is that such dryers use significant (many might say excessive) amounts of energy. The average full-sized 240 volt, clothes dryer consumes power on the order of about 4000 to 7000 Watts, such that the clothes dryer typically consumes energy at a higher rate than any other appliance in a home except for the household refrigerator. This is particularly undesirable in the case of conventional gas-powered and electric clothes dryers, given the costs and environmental impact associated with consuming such energy resources.
Further, not only do conventional clothes dryers demand heavy amounts of power, but also such conventional clothes dryers fail to make efficient use of this power. In order to heat articles of clothing for drying purposes, these appliances rely on either a gas-based or electric-based heat source that the U.S. government itself (e.g., the Department of Energy) apparently does not consider to be particularly energy efficient. Indeed, clothes dryers are so inefficient that no clothes dryer on the market is currently listed as qualifying for the U.S. Government's Energy Star rating (see www.energystar.gov).
The poor efficiency of conventional clothes dryers is largely due to the fact that clothes dryers simply do not use large amounts of the energy that is input to the dryers. Most conventional clothes dryers operate by passing dry, heated air around and through the clothes being dried, such that the clothes are heated up and moisture within the clothes evaporates. The heated, moist air is then exhausted out of the dryer and out into the environment (typically, outside the facility housing the dryer). Given this design, clothes dryers continuously expel, as waste, large amounts of heat energy during operation and, indeed, much of the heated air that is directed toward clothes during operation of the dryer simply passes by the clothes and is vented out of the machine without ever contributing to the drying of the clothes.
Clothes dryers also waste heat energy in other ways. For example, much of the heat generated by clothes dryers simply escapes from the dryers due to some combination of radiation, conduction, and convection before the heat ever reaches the clothes. Further, even to the extent that the heat generated by a clothes dryer reaches and heats the clothes, the energy still is often wasted. In particular, once the clothes drying cycle has been completed, the heat energy stored in the clothes further is wasted, as the clothes sit idle within the clothes dryer. Thus, clothes dryers not only require undesirably large amounts of energy in order to operate, but also waste significant portions of that energy.
What is needed is a clothes drying machine that uses less energy and/or is more energy efficient than conventional clothes drying machines, while still providing similar drying capabilities (e.g. while still drying significant amounts of clothes in comparable amounts of time).